DALLAS -- In discussing what the Steelers must do to make headway against the Packers in Super Bowl XLV on Sunday, guard Chris Kemoeatu ran down a series of typical Xs and Os but tagged his remarks by saying, most importantly, the offense needs to find where outside linebacker Clay Matthews is lined up.

Being singled out for game-plan preparation is now the measuring stick to being deemed bona fide, and Matthews, in his second exceptional season, has arrived. At least to the NFL and its followers. Not to him.

"Even though I was a first-round pick, Pro Bowler, I never feel like I've arrived," Matthews said.

Matthews reached star status quickly in the NFL, but it was getting to the league that was the hard part. His family bloodlines -- his grandfather, father and uncle played in the NFL -- opened some doors and provided him a head start in life, but not necessarily in football. His dad Clay, a former linebacker with the Browns and his high school position coach, didn't start him for part of his high school career because he was too small.

The younger Clay eventually blossomed and turned into a solid prep player at Agoura High School outside of Los Angeles, but he had to earn everything at Southern California, where he was a walk-on before getting a scholarship.

"He had a secret that he would slowly let us in on, but it was a secret that only he knew about," said Seahawks linebackers coach Ken Norton, who coached Matthews at USC. "From being a smaller guy who had to walk-on to working even harder when he finally did get a scholarship to where he was now, he has a chip that he can't let go of.

"I've always told him that chip is what makes you, and he has always kept it. He's really proud and he's really grounded and he's always trying to prove himself. We see the great player in the NFL, but Clay will always see that young player coming out of high school that didn't get a scholarship. All those guys who got scholarships, he was trying to prove that he's better than them. All those great linebackers that were there when he arrived and who came up with him, he was always trying to be better than them. He's always unsatisfied. As long as he has that, he'll be the best linebacker in the league for a lot of years to come."

That chip is real. During the Media Day interview session on Tuesday, a question for Matthews was preceded by the reporter telling him that he wasn't overly fast or strong. Matthews bristled before providing a composed response:

"If I'm not the swiftest, strongest, or fastest, it's really what comes from within," he said. "That's what determines how successful you're going to be. You don't have to be the biggest, strongest or fastest. It's your 'want to.' For the most part, if not all the time, I want to be great and be better than the person lined up in front of me."

It wasn't easy for Matthews to come out of high school as a player with a blue-blooded NFL pedigree who wasn't quite big enough to whet many major colleges' appetites. As a walk-on, like so many players hoping to earn a break, Matthews spent every minute he could working to get bigger and better while trying to catch Pete Carroll's attention.

"You could tell he had the potential physical makeup and the definite mental makeup where he stood a chance," Norton said.

The key to opening the door was Matthews' intellect, Norton said. He paired his late-arriving physical maturity with a firm knowledge of the system to move further up the depth chart. That pushed him onto special teams, where he was a monster. Norton said coaches would spend time wondering how they could get him onto the field. He still didn't quite fit any particular role, but he was such a disruptive player that they were forced to find him more opportunities to make an impact. As a result, they moved him into a hybrid end/linebacker role.

Once he got defensive snaps, the mission was to become great. By the time he finished his college career, he was good -- first-round-draft-pick good. Still, there was uncertainty as to whether he was a full-time outside linebacker or a valued pass-rushing specialist. He also was dogged by suspicion that his significant growth (Matthews currently is listed at 6-foot-3, 255 pounds after coming to college at about 200 pounds) during his time at USC wasn't all natural, even though he never tested positive for performance enhancers.

Genetically, though, his growth makes sense as his father Clay (6-2, 245) was a similar size. His younger brother Casey (6-1, 235), who played linebacker at Oregon and will be in the NFL next season, also is in that height and weight ballpark.

Doubt. Questions. Fuel.

"I don't think I'd be in the position I'm at today if it weren't for all the setbacks, people telling me I couldn't do it," he said.

Landing in Green Bay was the perfect fit. He's part of a roster made up of guys who've been doubted, and their hunger to prove themselves is what's allowed the Packers to overcome an absurd amount of injuries and make the Super Bowl despite being the NFC's sixth seed. Matthews also fell into a system schemed by Dom Capers and a position coach in Kevin Greene, who was one of the fiercest outside linebackers in NFL history.

Greene says he tries to instill some of how he played in Matthews but that Matthews is his own man doing his own thing and doing it well. He has 23.5 sacks in two seasons and finished second to Steelers safety Troy Polamalu for NFL Defensive Player of the Year this season.

Bengals left tackle Andrew Whitworth said Matthews is probably the second-toughest player he's had to block (behind Pittsburgh outside 'backer James Harrison) because of his speed and incredible strength. Matthews is a pure effort pass-rusher who Capers gets in positive matchups, but that's not to take away from his rare skills as a sack artist.

"Clay has a knack for how to rush," Norton said. "He's strong, light on his feet. He can play over the tight end or in space. He's got great football speed. His greatest strength is his football IQ."

Matthews isn't just a pass rusher. He's also solid against the run. In Green Bay's first game against Atlanta this season, the Falcons' plan was to challenge Matthews and the Packers' linebackers head-on. Attack and ramrod. A league source said they wanted to find out if Matthews was up to playing "big-boy football." The Falcons brought it and Matthews was held to four tackles and no sacks in Atlanta's 20-17 victory.

Falcons players figured they could have their way again when the teams hooked up in the divisional round of the playoffs. Matthews and the Packers' defense was so motivated by what happened the first time -- and some comments by Atlanta's players -- that they brought it to the Falcons, whipping them, 48-21. Matthews had four tackles and two sacks, and pretty much had his way.

Teammate A.J. Hawk said everyone on the team knows that Matthews is going to outwork whomever he goes up against and that he thrives against any sort of competition. Players look to him to make plays. And he's played huge in the postseason. In Green Bay's three-game road trek to the Super Bowl, Matthews has 13 tackles and 3.5 sacks, and, as Kemoeatu said, prompted offenses to pay him added attention.

Despite all of that, Matthews remains unimpressed.

"I've kind of had to scratch and claw for everything to get where I'm at," he said. "There's always something to accomplish and that's what I'll continue to do for the rest of my career."